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(No Model.) 4 Sheets-Sheet 1.

Y 0. D. ROGERS. W001) SCREW AND METHOD OF MAKING THE SAME. No. 479,175.Patented July 19, 1892.

INVENTOR- 4 Shets-Sheet 2.

no Model.) G. D. ROGERS.

WOOD SCREW AND METHOD OF MAKING THE SAME. No. 479,175. Patented July 19,1892.

, V WITNESSES. F INVENTEIFM W 4 (Rum-V05 .Kogvcl fivym 6 Z7,

(No Model.) 4 Sheets-Sheet 3.

O. D. ROGERS. WOOD SCREW AND METHOD OF MAKING THE SAME.

No.479,175. Patented July 19, 1892.

WITNESSES. INVENTDR. AQKYUS Q-vxegws. 7. -4# W ---'-/'T (No Model.) 4Sheets-Sheet 4.

C. D. ROGERS. W001) SCREW AND METHOD OF MAKING THE SAME.

No. 479,175. Patented July 19, 1892.

INVENTOR- UNITED STATES PATENT ()FFICE.

CHARLES D. ROGERS, OF PROVIDENCE, RHODE ISLAND, ASSIGNOR TO THE AMERICANSCREW COMPANY, OF SAME PLACE.

WOOD-SCREW AND METHOD OF MAKING THE SAME.

SPECIFICATION forming part of Letters Patent No. 479,175, dated July 19,1892.

Application filed June 21, 1888- Serial No. 277,776- (No model.)Patented in England January 4, 1889, No. 9,271; in France June 11,1889,No. 198817; inBelginm June 15,1889,No-86,646; in Italy June 30,1889, No-25,639, and in Canada November 8, 1889,10. 32,765.

To all whom it may concern:

Be it known that I, CHARLES D. Returns, a citizen of the United States,residing at Providence, in the county of Providence and State of RhodeIsland, have invented certain new and useful Improvements in Wood-Screwsand Method of Making the Same, (for which I have obtained Letters Patentin Great Britain, No. 9,271, dated January 4, 1889; in

France, No. 198,847, dated June 11, 1889; in Belgium, No. 86,646, datedJune 15, 1889; in Italy, No. 25,639, dated June 30, 1889, and in Canada,No. 32,765, dated November 8, 1889;) and I do hereby declare thefollowing to be a full, clear, and exact description of theinvention,such as will enable others skilled in the art to which itappertains to make and use the same, reference being had to theaccompanying drawings, and to letters of reference marked thereon, whichform apart of this specification.

Wood-screws hitherto have been made by a series of operations, which maybe specified as follows, omitting the drawing of the metal into wire andbeginning with the operation which has specific reference to the makingof a screw: first, the cutting from wire of a piece required for ascrew; second, the swaging of a rough head upon one end of the piece cutoff for a screw by upsetting the metal in a die by means of a machineknown as a header or heading-machine, (the piece of metal is now calleda screw-blank third, the shaving of the entire head thus formed to 5perfect its form and give it the required size; fourth, the cutting of aslot across the face of the head; fifth, the reshaving of the head. toremovethe burr formed in cutting the slot; sixth, the cutting away ofthe metal at the opposite end of the piece to reduce it to a point;seventh, the formation of the thread by cutting a spiral groove around aportion of the body of the wire or screw-blank, so-called. Thecutting-tool is applied to the blank several times, making repeatedcuttings to complete the thread. In these operations about forty percent. of the metal is cutaway and becomes waste.

1 have devised a new way of making screws by a different series ofoperations by which a large saving of material is eifected, a reductionin the cost of making secured, together with new characteristics andqualities in the screws themselves, which are the result of some of theoperations performed and are made necessary by those operations.

As in the old process, screws are made by my new process from wire; butfor screws of any specified size the wire is of a smaller diameter, thesize having reference to the diame- 6o ter of the threaded part of thescrew; but experience has proved that the size of the head should bearwithin small limits of variation a certain relation to the diameter ofthe thread, and the use of smaller wire for screws of specified sizesthan that which has been employed in the old process involves theupsetting of the metal to form the head to a greater extent thanheretofore and with an accuracy not before required both as to form andsurface.

In my new way of making screws the shaving of the head and the cuttingof the slot across it and the reshaving and the cutting away of themetal to form the thread are entirely dispensed with, and the consequentwaste of material is entirely obviated. The severing from the wire ofeach piece required for a screw is effected conjointly with the pointingof the blank by an operation which involves but little waste and bearsas much or more resemblance to forging or swaging as to cutting and isentirely different from the common method of pointing a blank by cutting away the metal as in a turning-lathe. At the same time the end ofthe wire is brought to a shape which facilitates the forging of the nexthead.

In my new way of making'screwsthe following operations are performed:first, the 85 head of ascrew, including the slot, is formed upon the endof a rod or coil of wire which is to be made into screws by swaging orforging; second, such portion of the wire on which a head has beenformed as is required for a 5 screw is then simultaneously cut off andpointed to a form and in a manner which will permit a thread to beforged thereon to the point of the screw; third, the thread is formed byrolling the body of the blank between dies, which force the metal toexpand radially into grooves in the die, which give the form requiredfor the thread.

The operation of swaging or forging the head, above referred to as adistinct operation, is, in fact, a complex operation of several steps orsub-operations similar in their nature, each differing from the stepsthat precede or follow it and requiring a specific device or instrumentto effect its specific object, but contributing to the final result-theproduction of a screw-head completely formed by forging or swaging.

The screw presents a surface of forged or compressed metal at the partswhich are subjected to the greatest strains, as at the junction of thehead with the shank, in theslot or neck, in the under surface of thehead, and in the thread. It is well known that iron or steel articleshaving such a surface are stronger than articles of the same size andform and of the same material with a surface formed by cutting. Testswhich I have made show thatscrews made by my new method with a forged orrolled surface in the parts above mentioned have greater tensilestrength and greater strength to resist the torsional strain of ascrew-driverthan screws of the same size made of larger wire and of thesame material. The diameter of the threaded portion of the screw beinggreater than the diameter of the unthreaded portion and the thread beingthinner, the required hold upon the wood can be secured with less dangerof splitting it than with screws of the common form. The slotin the faceof flat-headed screws being closed at the ends, the liability of thehead to split or break is greatly reduced. The screwdriver is also morereadily applied in line with the axis of the screw and with less dangerof marring the surface of wood into which a screw is inserted. Thesurface of the head which rests upon the wood and compresses it, andconsequently the area of the compressed section of the wood itself, islarger than in the wood-screws heretofore made by the common. cuttingoperations, and thus the wood is better able to resist the compressionof the screw. Other forms of heads can be forged by suitable dies, suchas spherical or conical heads, where the slot may be open at the ends inthe usual manner. The thin raised thread, which enters the wood morereadily than the common cut thread and engages with it more deeply,requires the strength due to the forged surface and the compression ofthe metal. The relatively small diameter of the wire employed to producea forged thread by radial expansion of the metal involves the upsettingof the metal to a greater degree to produce a head of the required sizeand makes it important to secure the strength due to a forged surface ofmetal.

The difference in the form of screws made by my new process is found inthe enlarged head and threaded portion of a screw relatively to theshank or unthrcaded portion.

It is obvious that the operations above mentioned must be performed bymachinery which has a definite relation to the results to be secured.

To enable others to practice the method of making screws which I havedevised and to make screws of the kind above mentioned, I will nowdescribe the operations in detail and specify the machinery and devicesrequired to perform them, much of which I have devised especially forthe purpose and have obtained patents thereon or made applicationstherefor.

In the first sheetof drawings hereto annexed I have shown in Figure 1 asectional view of the parts of a machine in which the operations offorging a head and pointing and cutting off a blank are performed. Themachine as a whole is described and shown in an application for patentof the United States which was filed by me July 7, 1887, and seriallynumbered 243,657. The second sheet represents in Figs. 2, 3, and tproper forms of dies for producing flat-faced heads with a forged slotclosed at the ends. In Fig. 5 dies are represented for severing a blankfrom the Wire, pointing its end, and molding the end of the standingwire preparatory to the forging of the next head. Fig. 5:}is an end viewof one of the dies enlarged. Figs. 6 and 7 show, enlarged, the roundedform given to the end of the wire in separating a blank and the form ofthe waste material forced out by the closing of the dies. Fig. 8 showsthe form of a screw-blank with a finished head and a conical point. Fig.9 is a plan of the face of a head with a forged slot closed at the ends.In Sheet 3, Fig. 10 shows a plan of the working face of one of a pair ofdies for forming thethreads of screws. The unshaded parts represent thefaces of the ribs which form the grooves in the metal and raise thethreads.

Fig. 11 is a longitudinal sectional view thereof, taken on lineacacofFig. 10. The unshaded portion represents the depth of the grooves or,what is equivalent, the height of the ribs or bars between the grooves.Fig. 12 is an enlarged cross-section of one of the dies, taken on lineto w, the two dies employed being duplicates. Fig. 13 is a cross-sectionof the two dies and of the screw in the operation of forming the thread,the dies being cut on line m on. These form the subject of a patent ofthe United States granted to me September 20, 1887, No. 37035;. Fig. 14,Sheet 4, represents in partial section a portion of a machine foroperating such dies and forging the threads of screws. It is describedat length in a patent of the United States also granted to me September20, 1887, No. 370,353. Fig. 15 rep resents a finished screw.

Referring to Fig. 1, 10 represents a wire which is to be made intoscrews. It first passes through a series of straightening-rolls an m, ofthe ordinary construction well known to mechanics. From these rolls itpasses between reciprocating feeding-clamps a, which IIO at the propertime grasp the wire and feed forward the length required for a screw. Itnext passes between a pair of clamping-dies b, which grasp it at theproper time and hold it firmly against the action of the headingvdiameter as the wire and through which the I -re'ady to receive theaction of the hammers,

v which acts upon it.

wire is forced by the feeding devices. On the opposite side from that atwhich the wire enters the hole is enlarged into an opening 6, usuallyconical, corresponding to the form ofthe screw-head to be produced,except as to its face. The wire is projected through the diesufficiently to furnish the metal required for the head. In thisposition it is which upset the metal, force it to fill the cavity of thedie, and give it the form required, the form of the face of the head,including the slot, being given by the last hammer Figs. 2, 3, and lillustrate theaction of each of three hammers which act in succession toproduce the most common and familiar screwhead. The first hammer doeslittle more than shorten the portion of wire protruded through the dieand enlarge its diameter, as repre sented in Fig. 2. The second hammercompresses the metal still more and expands it against the surface ofthe mouth of the die. This hammer also gives a temporary curved form tothe face of the head to prepare it for the action of the third and lasthammer. The necessity for doing this and the form of the hammer requiredis explained in an applica tion for United States Patent filed by meJuly 7, 1887, Serial No. 243,674. The action of the second hammer isillustrated in Fig. 3. In Fig.4the action of the final oriinishinghamlner is illustrated. The face of the hammer rests upon theface of the die and the cavity of the die is completely filled with themetal without overflow. A tongue 2? on the face of the hammer to formthe slot is represented by dotted lines. The operation of forging thehead a of a screw is now complete. If the face of the hammer and thesurface of the cavity of the die are smooth, the head of the screw willbe sufficiently smooth for the practical use of screws. If a finerfinish or sur face on the face of the head is desired, it may be givenby a suitable polishing or shaving tool without changing the characterof the head or the process by which the screw is formed. The head beingformed, the wire is next fed forward the proper distance for the lengthof screw required. The forging of the head expands the metal in thecylindrical part of the solid heading-die and makes it important thatthe wire shall be started by a feeding device of great power, followedby the action of 7 another device which carries the wire forward therequired length for a screw. The blank 0 is then severed from the wire.In connection with the severing Iperform the operation of pointing theblank to prepare it forthe threading operation.

The operation of severing and pointing is effected by means of a pair ofdies 8, (one of which is represented by Fig. 5%,) which are forcedagainst'the wire and compress the metal and bring the end of the blanktoa conical point 0 as represented in Fig. 5. At the same time the endof. the wire from which the blank is severed is brought to a globular orrounded form, as represented at c in Figs. 5, 6, and 7. This shape is ofadvantage in forging the next head. The dies which effect these resultsare shown by Fig. 5%, as just stated.

I do not regard the severing and pointing of the blank simultaneously tobe an essential part of my process. Neither is it in my judgmentessential that these operations should follow the heading operation; butI think the order I have indicated to be the best way of practicing myprocess.

The only waste of metal which attends my way of making screws occurs inthe severing and pointing of the blanks, and is represented at 0 0 inFigs. 6 and 7.

The final operation is the forging or swaging of the thread. Thisiseffected by means of two dies D, between which the blank 0 is rolled.These dies are represented in Figs. 10, 11, 12, and 13. Fig. 13 exhibitsthe blank in the operation of rolling and shows how the metal is forcedto expand into the grooves f of the dies. Fig. 10 is a plan of the working face of a die. The light spaces represent ribs T, which enter themetal at their narrow ends (the left being the entering end) to thedepth required to produce the thread r of a screw. Fig. 13 is atransverse sectional View taken through a pair of dies, show ing thescrew in the early part of the operation of forming the thread. Thesedies, as before stated, form the subject of a patent granted to meSeptember 20, 1887, No. 370,354,

where they are more fully described. I would state, however, that by theemployment of myimproved dies the pressure upon the metal toward theaxis of the blank is limited to the commencement of the rollingoperation and to a comparatively small part of the metal displaced. Theworking parts of a die D are the ribs '1" between the grooves f and theinclination of their adjacent sides to each other, which is constantfrom one end of the die to the other. The work of raising the thread ismainly performed by these sides. The angle of the inclined sides is thesame in all and the same from one end of the die to the other; but theheight of each rib and the width of its face or top varies throughoutits length and is determined at every point by the depth of the groovesadjacent to it. This top face, which is substantially level, has theform of a truncated wedge very narrow at the end (at the left) where therolling commences and much wider at the opposite end. lhis width or faceof the ribs 0* at the finishing end is the same width as the core of thescrew lying between two adjacent threads.

In order to roll threads upon a blank 0, the latter are placed in ahopper connected with a machine provided with suitably-mountedrolling-dies D. A machine of this character is indicated by Fig. 14, aportion of the machine being broken away to show the actuatingmechanism, and also showing a blank in the act of being operated upon bythe rollingdies. To roll a screw, the blanks are fed to a holder orsupport and held in a vertical position between the opposed ends of thedies, and (supposing one die to be stationary) as the movable die iscarried or forced ahead the blank is seized and rolled along betweenthem until the movable die passes the opposite end of the fixed die,when it drops from them completed, as indicated by A in Fig. 15. At thecommencement of the operation the narrow ribs of the dies are forcedinto the metal to the maximum depth required, and as the roll ingprogresses the metal between the ribs is more and more compressed andgradually expands into the grooves of the dies, until at the end of theoperation it fills them and the thread is completed. It will be seenthat in this series of operations all parts of the metal which arechanged in form are subjected to compression to effect that change, andthat thereby a large reduction in the waste of metal is effected, andthat, also, an important increase in strength is secured, due to thefact that at the parts especially where the strain in the use of thescrew is most severe a surface of compressed and compacted metal isobtained and preserved, resulting from the forging operations. Thisincrease in strength,

together with the improved form which results from the raising of thethread radially by rolling in the manner described, and the consequentchange in the size of the head with reference to the wire from which itis formed, makes an improved screw distinctively and substantiallydiiferent from the screws heretofore made by the process of shaving andcutting.

I claim- 1. The method of forming screws herein described, by forging afinished screw-head, including the slot, upon the end of the wire fromwhich screws are produced, cutting off from the wire and pointing bycompression between dies a piece of the required size to form a screw,and forging a thread thereon by rolling it between dies, the ribs ofwhich at the commencement of their operation penetrate the metal to therequired depth and then force the metal by lateral compression to expandradially and give the required form to the thread.

2. The wood-screw herein described, having the surfaces of its solidthread, which is raised from the body of the blank by rolling it between dies that compress laterally the metal to form the thread andforce it to expand radially from the blank into grooves in the dieshaving a form transversely the counterpart of that to be given to thethread, of the top and underside of the head, of the slot in said head,and of the portion of the shank adjacent to the head of the thread allcomposed of compressed metal, substantially as described.

I11 testimony whereof I have allixed my signature in presence of twowitnesses.

CHARLES D. ROGERS. \Vitnesses:

J osnrn SANFORD,

:lEO. II. REMINGTON.

